1. Technical Field
The present invention relates to a structure for introducing a plurality of solutions (a sample and/or a reagent solution) into a channel, in particular a channel of micro fluidic device, a micro fluidic device having said structure, a method for introducing a solution using said device, a method for separation of a substance and a method for measurement of a substance.
2. Background Art
Analysis of an analyte in a sample usually requires mixing a plurality of solutions such as a sample and various reagent solutions (for example, a reagent solution including an antibody to an analyte, a reagent solution containing a labeling substance, and the like) etc., and subjecting an analyte in a sample and a reactant in a reagent solution (an antibody to an analyte or a labeling substance, and the like) to a reaction.
In “Micro Total Analysis System (μ-TAS)” using micro fluidics device, technology thereof has recently been developing and various researches thereon have been made, and as a method for introducing a plurality of solutions such as including an antibody for an analyte or a reagent solution containing a labeling substance, and the like) into a channel, for example, the following method for using micro fluidics device having various structures has been known.
For example, there is a method for making a plurality of solutions presence in a main channel, by using a micro fluidic device (FIG. 1(a)) with a structure (a cross type structure) having a plurality of a side channel crossed a main channel for electrophoresis, wherein one end of said side channel is connected with a solution reservoir and the other end is connected with a waste reservoir, and by making a solution presence in a main channel by transferring the solution fed to a single solution reservoir into a single waste reservoir, and by carrying out this operation on a plurality of different combination of a solution reservoir (FIG. 1(b)) and a waste reservoir for a plurality of different solutions (FIG. 1(c)).
In addition, there is a method for making 2 solutions present in a main channel, by using a micro fluidic device (FIG. 2(a)) with a structure (a double T-form structure) having 2 side channels for introducing a solution communicated to a main channel for electrophoresis and one side channel for drain communicated to a main channel between said 2 side channels, wherein the end of said side channel for introducing a solution is connected with a solution reservoir and the end of said channel for drain is connected with a waste reservoir, as is shown in JP-A-2003-534532 (Patent Literature 1), and by transferring each different solutions fed to 2 solution reservoirs into one waste reservoir (FIG. 2(b)).
However, in the former method, because the volume of a solution introduced in a main channel is limited to the volume of a crossed part between a main channel and a side channel (FIG. 1(c)), much amount of a solution cannot be introduced in a main channel. In the latter method, although much amount of a solution can be introduced in a main channel, introducing only an objective solution into a main channel is difficult in the case when using pressure difference in (pressure control for) introducing a solution into a main channel because a solution (for example, a buffer for electrophoresis, and the like) other than an objective solution flows into the objective solution from the main channel (a white part shown by arrow mark in FIG. 2(b)). As a result, there is a problem that it is difficult to introduce an objective solution into a main channel by highly accurate volume. In addition, when a solution is introduced into a main channel electrically by applying electric field from a solution reservoir to a waste reservoir, only a substance (solution) having a charge can be introduced into a main channel. Furthermore, there is a problem that the introduction time must be severely set to a certain degree depending on kind (difference in mobility) of a charged substance (solution) because introduction time varies depending on difference in mobility of a charged substance (solution), or a problem that electrophoresis mobility is varied as a result of variation of electrophoresis mobility condition such as buffer property (pH) because of electrolysis generating in a solution by application of electric field.
Patent Literature 1: JP-A-2003-534532